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on Network Economics |
| By: | Alireza Abbasi; Jorn Altmann (Technology Management, Economics, and Policy, College of Engineering, Seoul National University); Liaquat Hossain |
| Abstract: | In this study, we develop a theoretical model based on social network theories and analytical methods for exploring collaboration (co-authorship) networks of scholars. We use measures from social network analysis (SNA) (i.e., normalized degree centrality, normalized closeness centrality, normalized betweenness centrality, normalized eigenvector centrality, average ties strength, and efficiency) for examining the effect of social networks on the (citation-based) performance of scholars in a given discipline (i.e., information systems). Results from our statistical analysis using a Poisson regression model suggest that research performance of scholars (g-index) is positively correlated with four SNA measures except for the normalized betweenness centrality and the normalized closeness centrality measures. Furthermore, it reveals that only normalized degree centrality, efficiency, and average ties strength have a positive significant influence on the g-index (as a performance measure). The normalized eigenvector centrality has a negative significant influence on the g-index. Based on these results, we can imply that scholars, who are connected to many distinct scholars, have a better citation-based performance (g-index) than scholars with fewer connections. Additionally, scholars with large average ties strengths (i.e., repeated co-authorships) show a better research performance than those with low tie strengths (e.g., single co-authorships with many different scholars). The results related to efficiency show that scholars, who maintain a strong co-authorship relationship to only one co-author of a group of linked co-authors, perform better than those researchers with many relationships to the same group of linked co-authors. The negative effect of the normalized eigenvector suggests that scholars should work with many students instead of other well-performing scholars. Consequently, we can state that the professional social network of researchers can be used to predict the future performance of researchers. |
| Keywords: | Collaboration, citation-based research performance, co-authorship networks, social network analysis measures, regression, correlation. |
| JEL: | C02 C13 C25 C43 C51 C52 D02 D85 H81 L25 M11 M12 O31 O33 |
| Date: | 2011–06 |
| URL: | http://d.repec.org/n?u=RePEc:snv:dp2009:201176&r=net |
| By: | Patacchini, Eleonora (Sapienza University of Rome); Zenou, Yves (Stockholm University) |
| Abstract: | We analyze the intergenerational transmission of the strength of religion focusing on the interplay between family and peer effects. We develop a theoretical model suggesting that both peer quality and parental effort are of importance for the religious behavior of the children. We then bring the model to the data by using a very detailed dataset of adolescent friendship networks in the United States. We find that, for religious parents, the higher is the fraction of religious peers, the more parents put effort in transmitting their religiosity, indicating cultural complementarity. For non-religious parents, we obtain the reverse, indicating cultural substitutability. Concerning the success in transmitting the religious trait, we find that, for religious parents, the fraction of religious peers has only an indirect effect (through parental effort) while, for non-religious parents, there is a lower indirect effect and a statistically significant and sizeable direct effect of peers on the transmission of the non-religious trait. |
| Keywords: | religion, cultural transmission, peer effects, network fixed effects |
| JEL: | A14 D85 Z12 |
| Date: | 2011–06 |
| URL: | http://d.repec.org/n?u=RePEc:iza:izadps:dp5787&r=net |
| By: | Filippo Belloc; Antonio Nicita |
| Abstract: | We empirically investigate the political determinants of deregulation policies in six network industries of 30 OECD countries over 1975-2007. We unbundle privatization and liberalization and propose an econometric study in which we allow for the joint adoption of the two policies by governments. We find, contrary to conventional wisdom, that right-wing executives tend to privatize more and to liberalize less, relative to left-wing governments. Thus, we show that ideological cleavages affect the ‘structure’ of deregulation, i.e. the way in which liberalization and privatization are combined. This result may shed new lights on the analysis of the political determinants of market-oriented policy, and suggest new issues for further theoretical and empirical research |
| Keywords: | Liberalization; Privatization; Network Industries; Partisanship. |
| JEL: | D72 L50 P16 C23 |
| Date: | 2011–03 |
| URL: | http://d.repec.org/n?u=RePEc:usi:wpaper:609&r=net |
| By: | Emanuela Marrocu; Raffaele Paci; Stefano Usai |
| Abstract: | This paper aims at assessing the role of various dimension of proximity on the innovative capacity of a region within the context of a knowledge production function where we consider as main internal inputs R&D expenditures and human capital. We want to assess if, and how much, the creation of new ideas in a certain region is the result of flows of information and knowledge coming from proximate regions. In particular, we examine in details the concept of proximity combining the usual geographical dimension with the institutional, the technological, the social and the organizational proximity. The analysis is implemented for an ample dataset referring to 287 regions in 29 countries (EU27 plus Norway, Switzerland) for the last decade. Results show that human capital and R&D are clearly essential for innovative activity but with an impact which is much higher for the former factor. As for the proximity and network effects, we find that geography is important but less than technological and cognitive proximity. Social and organizational networks are also relevant but their role is more modest. Finally, most of these proximities prove to have a complementary role in shaping innovative activity across regions in Europe. |
| Keywords: | knowledge production; technological spillover; proximity; networks |
| JEL: | O31 C31 O18 R12 O52 |
| Date: | 2011 |
| URL: | http://d.repec.org/n?u=RePEc:cns:cnscwp:201109&r=net |
| By: | Arnaud Dragicevic; Bernard Sinclair-Desgagné |
| Abstract: | We propose a dynamic graph-theoretic model for ecosystem management as a control over networked system composed of target nodes and unmarked nodes. The network is represented by a complete graph, in which all vertices are connected by a unique edge. Target nodes are attracted by the objective function issued from the external ecosystem management. They pull the network towards the objective position, which is either non-null or stationary. The management policy is considered successful if the graph remains connected in time, that is, target nodes attain the objective and unmarked nodes stay in the convex hull. At the time of the ecosystem network transfer, the model yields an Impossibility Theorem as well as a Sustainability Criterion to maintain full connectivity of the network. The latter can be easily linked to the general definition of sustainability as ecosystem integrity preservation. At last, we identify three management rules to ensure the maintenance of connectivity in time, given the properties of the objective transposition function, the nature of connections and utility updating time-delays between the nodes <P>Nous proposons un modèle dynamique de gestion des écosystèmes par la théorie des graphes en tant que contrôle d’un système en réseau composé de nœuds cibles et de nœuds non identifiés. Le réseau est représenté par un graphe complet dans lequel tous les nœuds sont connectés par une arête unique. Les nœuds cibles sont attirés par une fonction objectif issue d’un processus externe de gestion des écosystèmes. Ils tirent le réseau vers la position de l’objectif qui peut être non-nulle ou stationnaire. La politique de gestion est considérée réussie si le graphe reste connecté dans le temps, c'est-à-dire que les nœuds cibles atteignent l’objectif et les nœuds non identifiés restent dans l’enveloppe convexe. Lors de la transposition du réseau écosystémique dans le temps, le modèle génère un Théorème de l’Impossibilité ainsi qu’un Critère de Durabilité qui maintient la pleine connectivité du réseau. Ce dernier peut aisément être relié à la définition générale de la durabilité comme la préservation de l’intégrité écologique. Enfin, nous identifions trois règles de gestion pour assurer le maintien de la connectivité dans le temps, sachant les propriétés de la fonction objectif de transposition, la nature des connexions, et les retards de réactualisation de l’utilité entre les nœuds. |
| Keywords: | bioeconomics, ecosystem management, graph theory, connectedness., bioéconomie, gestion des écosystèmes, théorie des graphes, connectivité |
| JEL: | Q2 Q5 |
| Date: | 2011–06–01 |
| URL: | http://d.repec.org/n?u=RePEc:cir:cirwor:2011s-51&r=net |